A passenger aboard a Pakistan International Airlines (PIA) flight accidentally opened the emergency exit door on Friday night while hunting for the bathroom, causing a seven-hour delay.

The plane was sitting on the runway waiting to embark when the incident took place. The woman got up from her seat — defying the seat belt signs, which were on — and she opened the emergency exit mistaking it for the bathroom door. As she opened it, an evacuation slide deployed from under the door.

“The PIA flight, PK 702, from Manchester to Islamabad, was delayed by seven hours,” said a PIA spokesperson to Gulf News. “The departure was delayed on Friday night when a passenger erroneously opened the emergency exit causing the emergency chute to activate.”

“As per standard operating procedure, the PIA had to offload nearly 40 passengers and their luggage,” the spokesperson clarified.

The flight eventually left many hours later with a much lighter passenger load. Thirty-eight people were pushed to another, even later flight because, with the slide gone, the plane’s evacuation capacity was lowered.

We regret the delay of PK771, which is an unfortunate consequence of the delay of PK702, caused due to a passenger opening the emergency door. We strongly urge passengers to follow security instructions as such mishaps result in inconvenience of hundreds of other passengers.

Passengers were placated with food and others received an overnight hotel stay and transportation. The delay of the flight also led to a domino effect on later departures, for which the airline apologized on Twitter.

“We regret the delay of PK771, which is an unfortunate consequence of the delay of PK702,” PIA tweeted. “…We strongly urge passengers to follow security instructions as such mishaps result in inconvenience of hundreds of other passengers.”

Air Marshall Arshad Malik, PIA’s chief executive, ordered an inquiry into the incident. The Independent reports that deploying an emergency slide is no small (or cheap) occurrence: it costs an airline anywhere between US$6,000 and $30,000 whenever one is inflated.

This isn’t the first time something like this has happened: on a Ryanair flight in January of this year, a man got fed up waiting to get off the plane after it landed and he opened the emergency exit to jump onto the aircraft’s wing.